What is the connection between this Parshah and the previous one (of Ben Sorer u'Moreh)?
Rashi: It teaches that if the boy's parents have pity on their son and do not bring him before the Beis-Din to be sentenced to death, he will turn to evil ways and end up being Chayav Misah anyway.
Whom does "Chet Mishpat Maves" incorporate?
Rashi, Ramban #1 (citing Sanhedrin, 45b) 1 and Targum Yonasan: It incorporates anyone who is sentenced to death by stoning - including someone who cursed Hashem.
Ramban #2 (citing the Chachamim in Sanhedrin, 45b): It refers exclusively to someine who cursed Hashem or who served Avodah Zarah. 2
Why does the Torah write "ve'Chi Yih'yeh be'Ish Chet Mishpat Maves ... " and not "be'Adam Chet Mishpat Maves ... "?
Sanhedrin, 47a: To preclude a woman who has been stoned, who is not hanged. 1
See Torah Temimah, note 155. See also Targum Yonasan on Pasuk 23 and Yayin ha'Tov.
Why does the Torah insert the word "Chet Mishpat Maves", which it will not do later in 22:26, in connection with a Na'arah ha'Me'urasah?
Oznayim la'Torah: To preclude from the Din of hanging a Ben Sorer u'Moreh, who is also killed by stoning, but who is killed because of what he will do, even though he is not currently Chayav Misah. 1
See Oznayim la'Torah.
Why does the Torah insert the (otherwise superfluous) word "ve'Chi Yih'yeh be'Ish Chet Mishpat Maves Vehumas"?
Sanhedrin, 46b: To teach us that Beis-Din kill him before he has been hung and not afterwards - as is the the way of Nochrim. 1
See Torah Temimah, note 156 and Oznayim la'Torah, who elaborates.
How is the man hanged?
Why does the Torah write "ve'Chi Yih'yeh be'Ish Chet", and not 've'Im Yecheta Ish'? Moreover "Chet" refers to Shogeg; and only a Meizid is subject to Misah?
Kol Eliyahu: Because it is speaking where the sinner sinned be'Meizid, and afterwards did Teshuvah mi'Yir'eh, in which case the Meizid becomes a Shogeg. In such a case the Heavenly Beis Din accepts his Teshuvah to exempt from Kareis, but a human Beis Din does not have the authority to exempt him from death, Malkos or payment.